Spray nozzle



Feb. 10, 1948. ROWELL 1 2,435,605

S PRAY NOZ ZLE Filed March 31, 1944 ilwuc H101, HERMAN L. Rom/ELL #44 Will-mm) Patented Feb. 10, 1948 FFICE SPRAY NOZZLE Herman'L. Rowell,United States Army Application March 31, 1944, Serial No. 528,914 a 2Claims. (01. 299-120) (Granted under the act of March3, 1883, as

amended April 30, 1928; 370 G. 757) The invention described herein maybe manufactured and used by or for the Government for governmentalpurposes, without the payment to me of any royalty thereon.

This invention relates to a type of spray nozzle particularly useful forextinguishing fires of materials such as magnesium bombs and liquidfuels which burn stubbornly at high temperatures.

Numerous spray nozzles are known to have been developed for firefighting and other applications, and many of these have been perfectedfor particular purposes. Yet, when the problem of quickly extinguishingburning magnesium bombs seriously arose, it was difiicult to find anyeffective spray nozzle for this purpose.

Nozzles which do not fully atomize a stream of water but emit a jet ofwater in the midst of a fine spray are not suitable because the let willmake a burning magnesium incendiary react with explosive violence. Onthe other hand, nozzles known to be designed for complete atomizationhave had various drawbacks in being expensively constructed, large,requiring inflowing feed streams of very high velocity, having smallorifices which become clogged, and in forming hollow sprays difiicuit tofocus and concentrate on a burning incendiary.

An object of the present invention is to provide a spray nozzle whichavoids the drawbacks noted and which has a simplified construction so itcan be made economically by mass production for wide distribution anduse.

In general, the nozzle of the present invention has a conical-shapedbody tapering from an upstream inlet to a downstream outlet or dischargeorifice and includes within the body a means for separating anaxially'fiowing solid stream of liquid into a plurality of spiralstreams changed in velocity and forced to impinge on converging innerwalls of the nozzle so that the liquid becomes fully atomized with lowresistance. The nozzle is adapted for attachment to pipe or hoseinstallations of various sizes and supplying liquid under variouspressure and velocity heads.

The fog-producing or atomizing action of the nozzle is mainly dependentupon the shape of the structure within the nozzle and its relationshipto inner walls of the nozzle body converging toward an outlet orifice.

Preferably, the inner structure comprises a solid plug tapered towardthe inlet and centrally disposed near the inlet of the nozzle with aseries of curved vanes or blades adjoined. The blades are disposed todivide the solid stream from the inlet into a plurality of spiralstreams curved toward the inner wall of the nozzle converging toward theoutlet orifice of the nozzle. Each blade has a concave surface which isnearly parallel for a, substantial portion to a plane along thelongitudinal axis of the nozzle beginning at the up stream edge of theblade, then curves more toward the upstream direction. The blades haveagradually increased thickness from both end tips or edges toward thecenter. The reverse side of each blade is convex and faces toward aconcave surface of an adjacent or neighboring blade.

At the discharge end of the nozzle, it is preferred to have an orificeoutlined by the thin edge of an inward projection triangular in crossvsection.

A spiral stream of liquid fiowing between two of the fixed blades isgiven an increased velocity by contraction'in cross section and isdiverted at a suitable angle from the axis of the nozzle toward thenozzle wall for impingement and. deflection toward the orifice, thusavoiding excessive resistance.

The principles of the nozzle will be explained in more detail withreference to the drawing which illustrates a practical embodiment of thetype of nozzle suited for extinguishing magnesium incendiary fires.

In the drawing:

Figure 1 is a sectioned, longitudinal side view of the nozzle body andholder assembly with a side full view of means within the nozzle forseparating a solid stream of liquid entering the nozzle into a pluralityof curved streams;

Figure 2 is a sectional view of the nozzle body along the longitudinalaxis of the nozzle;

Figure 3 is a perspective side view of the tapered plug and blade means;and

Figure 4 is a cross-section view taken along the line A-A in Figure 1and in the direction of the arrows.

Referring to the drawing. and in particular to Figure 1. the holdercomprises'a tubular body I threaded internally at the inlet end 2 andexternally at the outlet end 3. Gaskets 4 are seated against a retainingring 5 within the body I adjacent to the internal thread 2 for making atight 3 discharge end II, but internally for a portion of the distancebeginning at the inlet, the walls may be substantially cylindrical, as,for example, up to a point l2, and thence be tapered to form an angle ofabout to 25 with the longitudinal axis of the nozzle as they converge tothe outlet orifice I3.

Close to the discharge end of the nozzle the gradual converging orarching of the inner wall, preferably ogival in contour, abruptly ends;and at this point, or slightly beyond, the inner wall slants sharplytoward the longitudinal axis, making an angle of close to 70 therewithand ending in the sharp tip l3, triangular in cross-section. The thinedge of this sharp tip is the perimeter of the outlet orifice. Itdefines the shape of the issuing mist stream. The orifice piece havingthe tip l3 may be in the form of a replaceable insert secured to thedischarge end of the nozzle or integral therewith. This piece may have acylindrical surface section which meets the end of the ogival surfaceand leads to the tip I 3.

The structure shown in Figure 3 is the means inserted within the nozzleclose to the inlet for separating the entering solid stream of liquidinto a plurality of curved streams. It is set into the nozzle as shownin Figure 4 with the tapered solid plug it centrally disposed and withthe adjoining curved vanes or blades l5 extending from the plug to thesurrounding inner wall of the nozzle. Four of these blades make asuitable number; and with four blades, each blade is radially positionedat 90 from an adjacent blade.

The blades are identically shaped with a concave surface l6 beginning atthe upstream edge approximately parallel to a plane through thelongitudinal axis of the nozzlea'nd then curving at a suitable angletoward a side of the nozzle and with a convex surface I! facing andconverging with the concave surface of an adjacent blade. It is alsopreferred to have the cross section of the blades gradually increasefrom both edges toward the centers.

With the blades thus shaped and positioned, a stream of liquid enteringthe nozzle is divided into four separate spiral streams, and each ofthese separate spiral streams first flows axially between a pair ofadjacent blades, then becomes curved and constricted in the narrowedpassageway between a concave surface and a convex surface near thedownstream ends of adjacent blades.

The center structure of plug and blades, conveniently made by casting asone piece, is readily inserted into the nozzle through the inletopening, and may be fixed in place by a set screw fastened into thedepression iii of a blade through threaded opening l9 in the nozzle walland by which then are directed out through the orifice on rebounding.The mass of droplet ejected from the orifice is substantiallyhomogeneous and bulb-like in form.

Spray nozzles of the type illustrated were made for fitting averagesmall-size hoses, such as might be found installed commonly in buildingswith 4 about 1% inch inside diameter and ordinary water pressures, andwere found to perform satisfactorily. They were also used in successfulairraid defense demonstrations of exemplary methods for extinguishingmagnesium incendiary bombs. It is considered that they are very effec-'tive for this purpose by virtue of the localized high-cooling action bythe quickly vaporizing fog they lay down surrounding a bomb.

An advantageous feature of the described nozzle is that the dividedliquid at all times has a substantially forward moving vector so that atno place is the flow completely obstructed. Another feature resides inthe shaping and positioning of the blades to impart increased velocityat the place in the nozzle where th impingement is to effect theatomization. With spiralling relatively high velocity, the liquid issubjected to several atomizing forces simultaneously, such as acentrifugal force, an impact force, and a forward velocity force.

With high efiiciency for completely atomizing a stream of liquid, spraynozzles embodying the features of thi invention are adapted to manyuses, as, for example, for precipitating dust, air washing, coolingponds, humidifying air, spraying liquids in condensers, atomizingliquids in vaporizers, reactors, dryers, absorbers,and the like. Thenozzles may be varied in size to suit the needs.

While, for the sake of simplicity, one type of nozzle has beenillustrated, it is to be understood that modifications may be made whichcome within the spirit of the invention.

I claim:

1. A spray nozzle for ejecting a homogeneous mass of liquid dropletscomprising a tubular conduit converging for at least a portion of itslength from an inlet to an outlet, a centrally spaced solid plug taperedtoward the inlet and spaced from inner surfaces of said conduit, a serieof blades disposed around said plug said blades having concave curvedsurfaces and convex curved surfaces, each of said blades having agradually increased thickness from the end tips toward their centers,and the distance separating the concave surface of one blade from theconvex surface of an adjacent blade becoming gradually smaller in adownstream direction.

2. In a spray nozzle for fully atomizing a solid stream of liquid, atset of radially spaced curved blades, each :blade having a relativelywide edge pointing substantially into an entering solid stream of liquidand a relatively narrow edge pointing downstream toward impingement wallsurfaces in said nozzle, and each blade having gradually increasedthickness from both said edges toward the center of the blade.

HERMAN L. ROWELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,282,176 Binks Oct. 22, 19181,367,769 Coffey Feb. 8, 1921 1,381,734 Parker et a1 June 14, 19211,442,356 Parker Jan, 16, 1923 1,496,924 Day June 10, 1924 1,506,722Yunker Aug, 26, 1924 2,047,716 Thompson July 14, 1936

